1. Field of the Invention
This invention relates to a magnetic alloy for magnetic recording-reproducing head and a method for producing the same. More specifically, the invention provides a high-permeability magnetic alloy for magnetic recording-reproducing head and a method of producing the same, which alloy essentially consists of, in percentage by weight, 60-86% of nickel (Ni), 0.5-14% of niobium (Nb), 0.001-5% in sum of at least one element selected from group consisting of less than 5% of gold (Au), less than 3% of silver (Ag), less than 5% platinum group elements (rhenium Re, ruthenium Ru, osmium Os, rhodium Rh, iridium Ir, palladium Pd, platinum Pt), less than 5% of gallium (Ga), less than 5% of indium (In), less than 5% of thallium (Tl), less than 5% of strontium (Sr), and less than 5% of barium (Ba), a small amount of impurities, and the remainder of iron. The alloy of the invention may further contain 0.01-30% by weight of at least one auxiliary ingredient selected from the group consisting of less than 8% of molybdenum (Mo), less than 7% of chromium (Cr), less than 10% of tungsten (W), less than 7% of titanium (Ti), less than 7% of vanadium (V), less than 10% of manganese (Mn), less than 7% of germanium (Ge), less than 5% of zirconium (Zr), less than 5% of rare earth elements, less than 10% of tantalum (Ta), less than 3% of beryllium (Be), less than 1% of boron (B), less than 5% of aluminum (Al), less than 5% of silicon (Si), less than 5% of hafnium (Hf), less than 5% of tin (Sn), less than 5% of antimony (Sb), less than 10% of cobalt (Co), and less than 25% of copper. The invention aims at the production a magnetic alloy having a high permeability, a high saturation magnetic flux density, a high hardness, an excellent abrasion resistance, a high forgeability, and a good workability, so that such alloy is particularly suitable for magnetic recording-reproducing head.
2. Description of the Prior Art
As the material for magnetic recording-reproducing heads, permalloy (alloy of Ni-Fe system) with a high permeability and excellent shapability and workability has been widely used. However, permalloy has a shortcoming in that its hardness is rather low, i.e. its Vickers hardness is only about 110, so that a magnetic head made of permalloy is rather quickly abraded by the contact with magnetic tape. Accordingly, there is a pressing need for improving the hardness of conventional alloy material for magnetic recording-reproducing heads.
The inventors have disclosed a high-permeability nickel-iron-niobium (Ni-Fe-Nb) alloy, with a high hardness and an excellent abrasion resistivity, in their U.S. Pat. No. 3,743,550. Continuous effort has been made by the inventors to further improve the properties of magnetic alloys of similar type.